<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Promise基本语法</title>
</head>
<body>
    <script>
        //实例化 Promise 对象
        const p = new Promise(function(resolve, reject){
            setTimeout(function(){
                //
                // let data = '数据库中的用户数据';
                // resolve
                // resolve(data);

                let err = '数据读取失败';
                reject(err);
            }, 1000);
        });

        //调用 promise 对象的 then 方法
        p.then(function(value){
            console.log(value);
        }, function(reason){
            console.error(reason);
        })
    </script>
</body>
</html>